psycopg2/examples/encoding.py

# encoding.py - how to change client encoding (and test it works)
# -*- encoding: latin-1 -*-
#
# Copyright (C) 2004 Federico Di Gregorio  <fog@debian.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.

## put in DSN your DSN string

DSN = 'dbname=test'

## don't modify anything below this line (except for experimenting)

import sys, psycopg
import psycopg.extensions

if len(sys.argv) > 1:
    DSN = sys.argv[1]

print "Opening connection using dns:", DSN
conn = psycopg.connect(DSN)
print "Initial encoding for this connection is", conn.encoding

print "\n** This example is supposed to be run in a UNICODE terminal! **\n"

print "Available encodings:"
for a, b in psycopg.extensions.encodings.items():
    print " ", a, "<->", b

print "Using STRING typecaster"    
print "Setting backend encoding to LATIN1 and executing queries:"
conn.set_client_encoding('LATIN1')
curs = conn.cursor()
curs.execute("SELECT %s::TEXT AS foo", ('<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", unicode(x, 'latin-1').encode('utf-8'), type(x)
curs.execute("SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", unicode(x, 'latin-1').encode('utf-8'), type(x)

print "Setting backend encoding to UTF8 and executing queries:"
conn.set_client_encoding('UNICODE')
curs = conn.cursor()
curs.execute("SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>'.encode('utf-8'),))
x = curs.fetchone()[0]
print "  ->", x, type(x)
curs.execute("SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", x, type(x)

print "Using UNICODE typecaster"
psycopg.extensions.register_type(psycopg.extensions.UNICODE)

print "Setting backend encoding to LATIN1 and executing queries:"
conn.set_client_encoding('LATIN1')
curs = conn.cursor()
curs.execute("SELECT %s::TEXT AS foo", ('<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)
curs.execute("SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)

print "Setting backend encoding to UTF8 and executing queries:"
conn.set_client_encoding('UNICODE')
curs = conn.cursor()
curs.execute("SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>'.encode('utf-8'),))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)
curs.execute("SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)

print "Executing full UNICODE queries"

print "Setting backend encoding to LATIN1 and executing queries:"
conn.set_client_encoding('LATIN1')
curs = conn.cursor()
curs.execute(u"SELECT %s::TEXT AS foo", ('<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)
curs.execute(u"SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)

print "Setting backend encoding to UTF8 and executing queries:"
conn.set_client_encoding('UNICODE')
curs = conn.cursor()
curs.execute(u"SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>'.encode('utf-8'),))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)
curs.execute(u"SELECT %s::TEXT AS foo", (u'<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>',))
x = curs.fetchone()[0]
print "  ->", x.encode('utf-8'), ":", type(x)